Nitroalkyl Acids

The addition of the carbanion from diethyl (3-butenyl)phosphonate to 1-nitroalkenes yields the stereoisomeric compounds (191).  

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Nitroalkyl Acids. - Additions of hydrogenphosphinic esters, Ph(R0)P(0)H, or diethyl (lithiodifluoromethyl)phosphonate to nitrostyrene or other nitroalkenes yield the nitroalkyl phosphonates (187) and (188), respectively. Diethyl (lithiodifluoromethyl)phosphonate also, by reaction with DMF, has provided (175), as already noted the condensation between the latter and nitromethane has given a 69% yield of (189) further reactions involving (175) (Scheme 12) have provided several additionally functionalized esters, amongst them (190). 

Data For Nitric Esters, Nitramines, Nitroalkyl-benzenes, and Derivatives of Phenol, Aniline, Urea, Carbamic Acid, Diphenylamine, and Tri-phenylamine , AnalChem 23,1740-7 (1951) CA 46, 5434 (1952) 71) T.L. Cottrel S. 

Carboxymethylcellulose, polyethylene glycol Combination of a cellulose ether with clay Amide-modified carboxyl-containing polysaccharide Sodium aluminate and magnesium oxide Thermally stable hydroxyethylcellulose 30% ammonium or sodium thiosulfate and 20% hydroxyethylcellulose (HEC) Acrylic acid copolymer and oxyalkylene with hydrophobic group Copolymers acrylamide-acrylate and vinyl sulfonate-vinylamide Cationic polygalactomannans and anionic xanthan gum Copolymer from vinyl urethanes and acrylic acid or alkyl acrylates 2-Nitroalkyl ether-modified starch Polymer of glucuronic acid... 

NITROALKYL PEROXONITRATES, NITROARYL COMPOUNDS NITROARYLPHOSPHINIC ACIDS, NITROBENZYL COMPOUNDS C-NITRO COMPOUNDS, A-NITRO COMPOUNDS ac/ -NITROQUINONOID COMPOUNDS, aci-NITRO SALTS POLYNITROALKYL COMPOUNDS, POLYNITROARYL COMPOUNDS POLYNITROAZOPYRIDINES Other relevant entries are ... 

NITROALKYL PEROXONITRATES NITROAROMATIC—ALKALI HAZARDS NITROARYL COMPOUNDS NITROARYLPHOSPHINIC ACIDS NITROBENZYL COMPOUNDS POLYNITROALKYL COMPOUNDS POLYNITROARYL COMPOUNDS POLYNITROAZOPYRIDINES... 

Finally, a series of o-nitroalkylanthraquinones184 and o-nitroalkyl-thiaxanthone-1,1-dioxides188 have been converted with fuming sulfuric acid into condensed anthranils (e.g., 100, X = CO, S02)-... 

Kende and Whiting reported radical cyclizations of equilibrium-generated enolates onto phenolates induced by K3[Fe(CN)6] however, these cyclizations were limited to the most acidic carbonyl precursors such as 1,3-diketones (equation 14a) or nitroalkyl compounds (equations 14b and 14c). 

The formation of nitroalkyl glycosides, illustrated in Figure 7.12, is limited in scope and few examples have been reported. The problems associated with this reaction involve the acidity of nitromethyl groups. Specifically, after formation of the C-glycoside, nitromethyl anions are easily formed. Moreover, when acetyl protecting groups are used, nitronates readily form. The few examples illustrated in this section are intended to convey the relatively limited accessibility of these compounds. 

A general route for the regiospecific synthesis of 3-alkylbenzopyran-l-ones, which occur in natural products, is based upon the formation of nitroalkyl-susbtituted isobenzofuranones from Henry condensation of nitroalkanes with phthalaldehydic acids. 

NITROALKYL PEROXONITRATES, NITROARYL COMPOUNDS NITROARYLPHOSPHINIC ACIDS, NITROBENZYL COMPOUNDS C-NITRO COMPOUNDS, A-NITRO COMPOUNDS... 

Manganese(III) can oxidize carbonyl compounds and nitroalkanes to carboxy-methyl and nitromethyl radicals [186]. With Mn(III) as mediator, a tandem reaction consisting of an intermolecular radical addition followed by an intramolecular electrophilic aromatic substitution can be accomplished [186, 187). Further Mn(III)-mediated anodic additions of 1,3-dicarbonyl and l-keto-3-nitroalkyl compounds to alkenes and alkynes are reported in [110, 111, 188). Sorbic acid precursors have been obtained in larger scale and high current efficiency by a Mn(III)-mediated oxidation of acetic acid acetic anhydride in the presence of butadiene [189]. Also the nitromethylation of benzene can be performed in 78% yield with Mn(III) as electrocatalyst [190]. A N03 radical, generated by oxidation of a nitrate anion, can induce the 1,4-addition of aldehydes to activated olefins. NOj abstracts a hydrogen from the aldehyde to form an acyl radical, which undergoes addition to the olefin to afford a 1,4-diketone in 34-58% yield [191]. 

Developments in the synthesis of (nitroalkyl)phosphonic acids and their phosphinic acid analogues, as a group, have occurred extensively only during the last 10-15 years, and the potential of such compounds in further synthetic procedures is only now becoming apparent. The number of methods available for the synthesis of (nitroalkyl)phosphorus compounds is appreciable and, as for the functionalized phosphonic acids discussed in the previous chapter, can be subdivided into those which depend on the formation of the phosphorus-carbon bonds and those which are based on modification procedures. 

One of the many uses to which (nitroalkyl)phosphonic derivatives are put is their reduction to the corresponding (aminoalkyl)phosphonic compound. The reverse reaction, that of oxidation of the amino compound to the nitro analogue, has rarely been adopted, a suprising observation in view of the multitude of procedures available for the preparation of the amino compounds. The oxidation of amino to nitro on C i) has employed KMn04 in acetone or acetic acid, but the yields are low acidic conditions have to be avoided, since (nitroalkyl)phosphonates then break down according to the Nef reaction . ... 

The most commonly adopted approach to the conversion of (hydroxyalkyl)phosphon-ic acids into the aminoalkyl analogues is through the intermediate (azidoalkyl)phosphon-ic acids (see Section IV. C. 1. f) although (aminohydroxyalkyl)phosphonic acids, in many cases readily obtainable through aldol reactions of (nitroalkyl)phosphonic acids, can be dehydroxylated (see Section IV. D.l). 

Several papers have been devoted to analogues of 4-(3-phosphonopropyl)-piperazine-2-carboxylic acid. One sequence, (Scheme 40), is initiated by the addition of (nitroalkyl)phosphonic diesters (410 R = Me or Et, n = 2 or 4) to A -protected -aminoacrylic ester, and leads, on the one hand, to the [Pg.172]

Nitroalkyl and Aminocdkyl Acids.-Ihn chemistry of nitro aliphatic organo... 

In a model synthesis <81CC524>, a nitro-Michael addition of the readily available nitroalkyl pyrrole 36 to mesityl oxide was used to introduce a geminally dimethylated structural element into an AD component rac-39 for the desired chlorin. Reduction of the nitro function in rac-37 leads to the desired AD dimer rac-38 which is combined in the presence hydrobromic acid with the well known a-bromo-a -bromomethyl dipyrromethene 40 after acid induced ester clevage and decarboxylation to yield the tetrapyrrolic biline rac-41. In the final step the linear tetrapyrrole rac-41 undergoes oxidation and cyclization in the presence of copper(II) acetate to give the copper chlorin. The cyclization occurs via the enamine tautomer of rac-41 by nucleophilic attack of the enamine structure on the bromo imine part of the linear tetrapyrrole. 

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